Method of fabricating vehicle control arms



Sept. 8, 1959 A. G. SCHILBERG METHOD OF' FABRICATING VEHICLE CONTROLARMS Filed April 24, 1957 EN TOR.

ILBERG 4" 4;- ,igalzw IN V ARNOLD G. SCH

ATTORNEYS.

ilnited States Patent METHOD OF FABRICATING VEHICLE CONTROL ARMSApplication April 24, 1957, Serial No. 654,743

1 Claim. (Cl. 29-416) This invention relates to a method of formingchannel section members having flanges of predetermined varying depthfrom relatively thin sheet material.

In the manufacture of vehicle control arms, a pair of complementarycurved channel section members are secured together along meeting flangeedges as by flash welding to form a generally X-shaped arm. Each'channel section member is formed from a flat blank cut from relativelythin sheet material; At the location of the meeting flange edges, eachblank is formed with a longi tudinal portion having increased depth toprovide burnofi material which is consumed during the flash weldingoperation. Because the weld extends only over a portion of the length ofeach channel section member, provision for the burn-ofl material on eachblank prevents economical nesting of blanks on the thin plate sheetingfrom which the blanks are cut. It is an object of this invention toprovide a method of fabricating channel section members having flangesof predetermined varying depth whereby material requirements during theblanking operation are reduced and scrap loss is minimized resulting insubstantial cost reductions over previous methods.

According to the invention, a channel section member having flanges ofpredetermined varying depth is formed from a sheet metal blank ofgenerally constant width. The blank is locally stretched and permanentlydeformed to increase the blank area over portions of its lengthcorresponding substantially to the portions of the finished channelmember where increased flange depth is desired. The blank is then formedinto a channel section member with the portions of increasedarea of thestretched blank providing the flange portions of increased depth.

The drawings furnished herewith illustrate the best mode of carrying outthe invention as presently contemplated and set forth hereinafter.

In the drawings:

Figure 1 is a diagrammatic elevation of a double acting press showingthin plate material secured against movement before the punch descendsto dish or bulge a blank;

Fig. 2 is a view similar to that of Figure 1 showing the punch dishing ablank;

Fig. 3 is a view similar to Figure 1 showing the punch dishing asubsequent blank while the shear is simultaneously actuated to cut off aconstant width blank having been previously dished; V

Fig. 4 is a plan view of a blank showing the dished or locally stretchedarea;

Fig. 5 is an enlarged diagrammatic representation in section showing theblank between the forming dies to form the blank into thechannel-section member having flanges ofincreased depth over a portionof the length of the channel member;

,Fig'; '6 is a views'iin'ilar to Fig? 5 ing dies in their fully close'dposition;

Fig. 7 is a side elevation of a formed channel member showing the'formice showing the increased flange depth over a portion of itslength;

Fig. 8 is a top plan view of a flash welded control arm wherein theportions of increased flange width along the meeting flange edges ofeach channel member have been consumed as burn-01f material;

Fig. 9 is a view taken on line 99 of Fig. 8; and

Fig. 10 is a diagrammatic representation showing an other method ofsecuring the sheet material against movement during the dishingoperation and wherein a plurality of blanks are dished simultaneously.

Referring to the drawings, the vehicle control arm 1 is fabricated froma pair of curved channel members 2 which are flash welded together overa portion of their length along their meeting flange edges. The channelmembers 2 are formed from blanks 3 having a generally constant width sothat economical blank nesting on a sheet 4 of thin plate material ispossible during the blanking operation.

According to the invention, a plurality of blanks 3 are laid out inseries on sheet 4 for a pierce and cut-ofl type blanking operation. Thesheet 4 rests on the bed 5 of a double acting press 6 and advancesthrough the press, as shown in Figs. 1, 2 and 3. A shear 7 is providedat the rearward end of the press 6 to cut off suc cessive blanks 3, asshown in Fig. 3.

The double acting press 6 includes a holddown member 8 and a ram 9 whichmove relative to the bed 5. The ram 9 is provided with a punch 10 at thelower end thereof for entering the cavity 11 provided in the bed 5 ofthe press. The holddown member 8 surrounds the ram and is provided witha holddown projection 12 rearwardly from punch 10. Forwardly of punch10, the holddown member 8 has a relatively large engaging surface toprovide the frictional resistance between the sheet and tool necessaryfor securing'the sheet 4 within the press 6. A cavity 13 is provided inbed 5 rearwardly of cavity 11 and parallel thereto for receivingprojection 12 of the holddown member 8 for clamping the sheet rearwardlyof the punch 10. The punch 10 and projection 12 and their respectivecavities 11 and 13 extend trans- 'versely of the pressa distancecorresponding to the longitudinal portion of channel 2 having increasedflange depth. The distance between the center lines of cavities 11 and13 corresponds to the width of blank 3.

After the sheet 4 is initially indexed within the press, the punch 10and holddown member 8 descend together toward the sheet. The holddownmember 8 engages the sheet to secure it Within the press and the punch10 continues downwardly to deform the sheet into the cavity 11 toprovide the bulge 14. The sheet is then advanced one blank width intothe press and the bulge 14 placed into cavity 13. The holddown member 8and punch 10 descend again with the projection 12 of the holddown memberengaging bulge 14 previously formed. In this manner, the sheet issecurely held rearwardly as well as forwardly of the punch 10 so that asthe punch descends to form bulge 14 in the next blank portion, thematerial is locally stretched to form the bulge. After the bulge 14 hasbeen formed in the second blank portion, the sheet is again advanced inthe press to place the last formed bulge into the cavity 13 so that thesheet may again be well secured forwardly and rearwardly of the punch10. As the press elements now descend to form bulge 14 in the next'blankportion, the shear 7 operates to sever the first bulged blank 3 from thesheet 4. This pierce-cutoff type operation is continued over the lengthof sheet 4.

After the individual blanks 3 are trimmed to provide rounded endportions, as shown in Fig. 4, they are subjected to 'a press formingoperation to form the blank into the channel section member 2, shown inFig. 7,

. 3; The forming operation is shown diagrammatically ,in Figs. 5 and 6,wherein the blanks 3 are placed between the ram and die 16 of the press.In the process of fo ming t h nnel se tieny-rnemhet .2,.-;th shn sedtpetion 14 is flattened into the web portion of the nnel and the-,increasedblank width -fifimdtl rhymtheblllg provides the channel -withincreased-flange depthqco rrespondin g -substantially to -the --lengthofqt he bulge As seen in Fig. 6 and Fig. 7, the-channel grnemher 2is formed with projectingflange-portions d7 aboye the'idotdash linescorresponding substantially etc-the length of bulge Byv s -theeliminatientef thezhdgeth P oje in p n 1 eshennehmemhw previ anincreased flange depthtover the flange dq ih-Qfithe r ma nd ftheichanehme her a As shown in :Figs Band; ;;a p ir \Qf channel members 2' a e.d spes d imfla g iacin relaticmen flash Welded er a th iein i erme u-hew enith pp p i ti g flan e :PQifiQHS; 11 in; the nam less of a g, theadded angeid nth -iport cns; -17 i burned rofi s ha t channe members 2 fc ntrol arm 1 have substantially constant flangeijdepthpyer their fulllength.

The method of the inveptiom-has been appliedqto ;a control arm blank 3incheswide and;h,aving,ganr original thickness of n. he blan -was leallvis re ched to fcrm a u e e ank e ndinglever a length r p ndi t thewel z area. Th mbulge: ex ended Over approximately lf w dthiof th ablanki l fir hfi reduced s te h kness the :bulg d ateaaa era about h rep enng a g uge reductidn: :of. over 16.5%. width of .the blank provided a10% increase -blank Width v r h ength of thezweld area r.ahQu -%s in h.

increase in flangedepth'which: was.,.available for flash -9 m d g'rbum-nfi ma erial; :inaccordance with themethod of invention.eliminatesmse-ofa bla k oumu ph ving tune enomieal lateral projections.

It is estimated ;that withtconstant-width:blanks the material savingrealized amounts to a-su'bstantial 17%,. Furthermore, because ,of {theinereasedastrength iresulting from the cold working. in, thebulgedareabthe reduced gauge thickness .of :that area [does notlafiectithezistrength of the finished channel member; I

While the ,:above figures. genera-llyw.-hold;ttrue tot-mall intermediateblanks 3 cut from sheet r4, there. .will; be some variation for :thefirstanddast.zblankshcutfrom the sheets When thesheetA'is initially.indexedinto. the press, the end thereof rests midway between :thecavities 11 and 13, as shown in Fig. 1, so. that the sheetis not engagedby projection. 12. of the. holddown. member .rearwardly of the punch 10.As alresult, when the punch 10 descends to place bulge 145 in the firstblank .portion, some material may be drawn in from the rearward edge ofthe sheet if the frictional resistance xdeveloped rearwardly of thepunch is inadequate. In the instance of the last blank portion, materialmay be .drawnin from the forward edge of the sheet iffrictionalfresistance. forwardly of punch 10 is inadequate. In:eithertcase, .the increase in blank width will: be somewhatrlessthan.120% over the length of. the weld area and may be compena satedfor, by providingpthe first and last. blank to. bet-cut from sheet 4with a corresponding. increase in width.

According to the embodiment shown in Fig. .110; the pierce-cutolf ,type.operation for forming the. blanks 3. i1.- lustrated in Figs. '1, 2 and3 is replaced ;by an. operation wherein spaced bulges 14:corresponding-to individual This a g red ction everabcuth lf/of the.carriesa plurality. of. spacedpunches. 23 which are adapted to enterthe intermediate cavities 21. The holddown member 24 extendssubstantially over the full length of the working bed 19 of the pressand surrounds the punches 23. Projections 25 and 26 extend downwardlyfrom the holddown memberiinralignment with cavities 22providedintherespective endsof .the.bed...1 9..

In the operationof-press.ZOJShQWnlinFig. 1'0, a sheet 4 is disposed overthebed 19 of the press and the holddown projectionsflS and 26 initially.engage -;thessheet. ..As :.the hold down. member. continues :down-wardlyi to clamp sheet 4 with respect to the bed, the projections 25and'26deforr the sheet .4 into. the end cavities 12 .to ;pr,ovide.bulges 14 inthe respective ends of the sheet to further secure the sheet. With thesheet-secured -in :this :manner by holddown member 24 the punches 23descend and deform the sheet 4 by locally stretching the material intothe intermediate 1 cavities 21 :to:fom1.=the;intermediate-' bulges 14.Thus, spaced bulges .14 corresponding-to zindividualiblank portions :areformed into thew-entire sheet A-imonepress operation. The.individualnconstant. .blanks 3 shown inHEigtA .are "thenasevereddrom thesheet ;and formed into channehmemhersilas hereinbeiore: described;

"While the end :cavities-.22 receiving .proiectionsfifi-zand 2610f theholddown member; 24. are shownrinuFig-zl .OitOF be similartozthe:intennediatecavities: 21,3;the .hulgesfo'rmed therein are.not:.wholly prodncedahyalncal stretching. As the holddown projections.25.:and- 260i Fig. .,1'0;-enter thecorrespondingcavities,2theenrhbulgeslarepartiallyformed by drawing:adjacent unsecured materialsiinto the cavities. As a result, thesbulges.14 :provi-dedxzimthe first :and last blank in-accordaneeWithLIthGIImBthIQd-COf Fig. 110 will pre vide somewhat.rlessiithan;.20i%-.increase :in blank fwid'th over :theilengthof weld joint 18.:similarly $0. the bulges in thefirst a andlast iblanlc of-athezpiercetcutoffatype:operation.

Various, modes of marrying ioutztheiinventinn :are:contemplated-asbeing: withimthet SCOPExflfithfliffilklwll'lgiclailnparticularly .pointing routtanddistinetly claiming the subject- =matterwhich is regardednsrthe. invention.

I claim-:- I

In a method .of '-:fabricating;.a;.uehicle control armcomprising,=securing asheetqf thinzplate material Which a pluralityv ofblanks-are.- .ztmbe; icut. against substantially allmovement intheplane-of thesheet;:stretchingpnrtions of the sheet. corresponding.toitliexindividual blanks y deforming gthe:materiaL-iinto;;dished.tnontoursunf. lesser width-thanathe blanlcandtextending; over a predetermined length of the blanlh zto; pmvideaeachblank- .an increased surface; area; tseveningtzthe zsheet. alongstraightlines extending substantially midway betweenwthe dished contourstoprevide separate. constantzwidt .hlank ,cf ing eaehiblankintoiaschannel;section rnember whereby of each blank is forced laterallyoutwardly with respect to the'bl'ank to provide .eaclnehannelg memberwith ;fl'ange portions of igreaten. depth dvercg saidipredeterm ned length than the depth of theremainden ofsthe :flanges, disposing blankportions are formed in the entire'sheet4 in a single press operation.The bed 19'ofthe1press 20. shown in Fig. 10 is Provided with a pluralityof longitudinally spaced and aligned intermediate cavities 21 and endcavities 22 which extend laterally in accordanceLtonthetlengthiof theweld joint 18 to be providedhetweenuthe channelvmembers 2 comprising thearm 1. The press ram, not shown,

the portions of the flanges having increased depth in =opposed; andspacedlzrelation; and flash; welding-thephannel.

members (t geth o er 1 k h ..%t ,e an depthnodorm the control arm withthe increasedlflan'ge material provided on the opposed flanges servingas ofimateiial torthe hash welding operation References Cited in thefileof this-patent- UNITED STATES PATENTS 1,715 ,135; V Lambert May ,28,1929 1,857,505 Heineman May 10, 1932 1,940,305 Kapitke Y. V Dec, 19,1933 1,994,428 Keil Mar.. 12, 1935

